Experimental Study Of The Flames Structure And The Charaterisctics Of Pollutant Emissions In The One-dimensional Counterflow ODPP/OESC Flames

The counterflow flat flames are used to study combustion theory in usual. Based on asimplified physical model, a counterflow flat flame experiments diagnostic system is builtto study the flame structure and the characteristics of pollutant emissions in theone-dimensional counterflow ODPP/OESC flames by both experimental diagnostic andtheoretical analysis.Existing on opposite sides of the stagnation plane for ODPP/OESC flames underexperimental conditions, the two flame zones consist of a premixed flame formed in thefuel-rich mixture and a nonpremixed flame formed between the products of this rich,premixed flame and the opposing air stream. The temperature of the premixed flame islower than the nonpremixed flame. Compared with the premixed flat flame whose fuel-sideequivalence is above2.0, the phenomenon of heave exists in the nonpremixed flame whosefuel-side equivalence is below2.0.Increasing fuel-side equivalence ratio, or reducing theconcentration of the oxygen-diluted in the fuel-rich mixture or the concentration ofoxygen-enriched in the oxidant, it is shorter for the distance between double flames, thinnerfor the thickness of the flame, lower for the flame temperature. Besides, simulations withthe CHEMKIN software show that model-data comparisons for temperature variation andthe pollutant emissions variation agree well with the experiments.Compared to full-premixed flame and partially premixed methane/air counterflowflame, the NOx emissions of the ODPP/OESC flames remain unchanged while the COemissions are reduced. Furthermore, it is helpful to reduce the CO and NOx emissions toreduce fuel-side equivalence ratio or the concentration of the oxygen-diluted in the fuel-richmixture or the concentration of oxygen-enriched in the oxidant.So, in conclusion, it is preferable for ΦP=1.3for the fuel-side equivalence ratio, ΦT=0.95for the total equivalence ratio,18%for the oxygen diluted concentration and25%foroxygen enriched concentration. NOx emission changes little and CO emission is reducedby48%by comparison to partially premixed methane/air counterflow flames, when theequivalence ratio of the premixed flow is the same.